Comment 5 for bug 338328

I didn't see any difference with
sudo mv /etc/acpi/events /etc/acpi/events.disabled

A workaround for the brightness problem is to blacklist the video module. I don't know if this is a good thing to do or not; but I've been using my laptop like this for a lot of months now without a problem.

With the video module *not* blacklisted:

alkisg@alkisg:~$ find /sys -name '*bright*' 2>&-
/sys/devices/platform/acer-wmi/backlight/acer-wmi/brightness
/sys/devices/platform/acer-wmi/backlight/acer-wmi/actual_brightness
/sys/devices/platform/acer-wmi/backlight/acer-wmi/max_brightness
/sys/devices/virtual/backlight/acpi_video0/brightness
/sys/devices/virtual/backlight/acpi_video0/actual_brightness
/sys/devices/virtual/backlight/acpi_video0/max_brightness
<...omitting some non-useful devices...>
/sys/module/video/parameters/brightness_switch_enabled
/sys/module/acer_wmi/parameters/brightness

With the video module *blacklisted*:

/sys/devices/platform/acer-wmi/backlight/acer-wmi/brightness
/sys/devices/platform/acer-wmi/backlight/acer-wmi/actual_brightness
/sys/devices/platform/acer-wmi/backlight/acer-wmi/max_brightness
<...omitting some non-useful devices...>
/sys/module/acer_wmi/parameters/brightness

So maybe the problem is that the video module adds a second, fake, brightness "device"?

In the previous hal.txt I attached, I'm afraid that I had messed with /usr/share/hal/fdi/information/10freedesktop/10-laptop-panel-hardware.fdi.

I include two versions of lshal:
lshal-1.txt => with the original 10-laptop-panel-hardware.fdi.
lshal-2.txt => again with the original 10-laptop-panel-hardware.fdi, but also with the video module blacklisted.